I. Introduction
The number of website users is on the rise, exceeding 4.54 billion active web viewers worldwide [1]. Moreover, there are approximately 1.72 billion websites accessible through desktops and smartphone devices [2]. However, research studies have reported that, on average, users abandon websites within the first 3 seconds due to diverse reasons, including the complexity and slow loading times of sites [3]. Therefore, developers must produce efficient yet compelling web designs that accommodate the taste of their users and keep up with the technological changes. Furthermore, current websites would need to be responsive to satisfy the enormous variability enforced by modern smartphones concerning screen size, resolution, and supported technologies. In user-centered software engineering, user testing is a vital ongoing activity to ensure that the software artifacts produced conform to the user needs and requirements, thus ensuring the highest levels of software acceptance and adoption by the end-users. However, conducting validation testing with real users is a sophisticated and laborious process that requires significant expertise, resources, and time.